Preventing people from using mobile while driving and door bell with visitor codes

To prevent people from using mobiles while driving, Rajashree suggests docking the mobile at a designated place in the vehicle to enable it to move. Thus, if a call has to be picked up, it can only be done when the vehicle has been stopped. Her second idea is a door bell with codes for different visitors. It is difficult to identify the visitor as the door bell gives only one sound. A numeric pad may be provided where friends and family members are given a code. When the person presses the digits of the code (eg 1-2-3), the bell (through ring or any other means) will identify the visitor.